Valved tree member for a riser system and telescoping device for inclusion in a riser system

ABSTRACT

A valved tree member ( 50 ) for inclusion in a riser completion system ( 35 ) and suitable for use in the region of a moon pool ( 14 ) on a floating vessel ( 8 ), the valved tree member ( 50 ) comprising:
         one or more valve members ( 70 ) adapted to selectively permit and prevent flow of fluid therethrough, and   one or more moveable stab members ( 76 ) adapted to respectively selectively provide a sealed fluid communication path between a throughbore of the riser system and the one or more valve members ( 70 ). A telescoping device ( 60 ) and a flow diverter member ( 66 ) for inclusion in the riser completion system ( 35 ) are also provided, as well as a riser completion system ( 35 ) incorporating the valved tree member ( 50 ), the telescoping device ( 60 ) and the flow diverter member ( 66 ).

BACKGROUND 1. Field of the Invention

The field of invention relates to offshore riser systems used in the oiland gas industry.

2. Background of the Invention

The present invention relates to an apparatus and method particularlybut not exclusively for use in the moon pool area of an offshore vesselused to install and support a riser system used to produce hydrocarbonsfrom a subsea well to a floating production facility or vessel on thesea surface and more particularly the invention relates to seeking toimprove safety by allowing the possibility of halting and diverting theflow of hydrocarbon product to or below the drill floor and alsoproviding the possibility of remote disconnection of the top levelequipment on the drill floor from the riser system below and thereforeallowing the possibility of work to be safely carried out on the toplevel equipment and/or the upper end of the riser system on the drillfloor without the heave hazard associated with sea and vessel movementrelative to the riser system.

Conventionally, hydrocarbons are produced from a subsea well through awellhead. A primary flow control system in the form of a christmas treeis located at the wellhead and which controls the flow of hydrocarbonproduct from the subsea well through the wellhead and through thechristmas tree into a riser system. The riser system consists of asufficient length of flexible riser in the form of a flexible flow lineor pipeline and which connects the christmas tree to a floatingproduction facility or vessel located on the sea surface such that theriser system delivers the hydrocarbon product to the floating facilityor vessel. The riser system is typically installed by a drill shiphaving a moon pool located in its center where all the equipment that isrequired when installing a riser system such as a lower riser package(LRP) and an emergency disconnect package (EDP) and the flexible riseritself can be lowered from the drill ship through the moon pool into thesea and down to the christmas tree.

Conventionally, work on the upper end of the riser system such asconnecting in or swapping out required top level equipment is normallycarried out with the drill ship moving relative to the sea bed/risersystem because of the sea swell and this causes significant safety andoperational problems when installing/changing such top level equipmentand therefore sea conditions have to be calm to proceed with any degreeof safety.

It would therefore be desirable to be able to safely work on the upperend of the riser system in conditions with some sea swell.

According to a first aspect of the present invention there is provided avalved tree member for inclusion in a riser system and suitable for usein the region of a moon pool on a floating vessel, the valved treemember comprising:

one or more valve members adapted to selectively permit and prevent flowof fluid there through, and

one or more moveable stab members adapted to respectively selectivelyprovide a sealed fluid communication path between a throughbore of theriser system and the one or more valve members.

Preferably, the valved tree member comprises a body member upon whichthe said one or more valves are mounted and typically, the one or morevalve members mounted thereon comprise a longitudinal axis arrangedsubstantially perpendicularly to a longitudinal axis of the riser systemat the point at which the valved tree member is included in the risersystem. Typically, the said one or more valve members are connected tothe body member by a tubular coupling having a throughbore and morepreferably, the said moveable stab member is located within thethroughbore of the tubular coupling. Preferably, the said moveable stabmember is arranged to selectively engage with a port provided in theriser system. More preferably, the port is included at a suitablelocation in the riser system and comprises at least an aperture througha sidewall of the riser system. Typically, the said moveable stab memberis arranged to selectively sealingly engage with the port provided inthe riser system. Typically, the said moveable stab member is arrangedto selectively move radially inwards toward the longitudinal axis of theriser system is a direction substantially perpendicular to thelongitudinal axis of the riser system to sealingly engage with the porthaving an aperture formed through the sidewall of the riser system suchthat fluid in the throughbore of the riser system may flow in a sealedmanner from the throughbore of the riser system through the moveablestab member and into the said one or more valves mounted on the valvedtree member.

Preferably, a flow diverter member is included in the riser system, theflow diverter member comprising a substantially vertical tubular memberhaving a longitudinal axis substantially parallel with and morepreferably substantially co-incident with the longitudinal axis of theriser system at the point at which the flow diverter member is includedin the riser system and more preferably the flow diverter member furthercomprises a cross tubular member which is more preferably arranged withits longitudinal axis to be substantially perpendicular to thelongitudinal axis of the substantially vertical tubular member.Preferably, the cross tubular member provides said port or aperture ateach end thereof. Typically, the flow diverter member comprises three ormore (and more preferably only four) fluid entry/exit points where twoare provided by each end of the substantially vertical tubular memberand two are provided by each end of the cross tubular member andtypically, the respective throughbores of the cross tubular member andthe substantially vertical tubular member intersect one another.

Preferably, the valved tree member is selectively coupled to a housingmember provided on the floating vessel and more preferably, the valvedtree member comprises a selective locking system to selectively lock thevalved tree member to the said housing member of the floating vessel.Typically, the valved tree member will be locked to the said housingmember when the riser system is being run into the body of water onwhich the vessel is floating, the riser system being run in through athroughbore of the valved tree member and through the moon pool of thefloating vessel.

Preferably, once the one or more valves of the valved tree member are insealed fluid communication with the throughbore of the riser system, theselective locking system may be unlocked to release the valved treemember from engagement with the housing member and one or more tensionsupporting members are provided to support the weight of the valved treemember. Preferably, the said one or more tension supporting memberspermit relative movement, typically relative vertical movement, to occurbetween the valved member (which is now secured to the riser system) andthe floating vessel such that the one or more tension supporting membersalso bear at least a portion of the weight of the riser system andthereby compensate for relative heave between the riser system and thefloating vessel.

According to a second aspect of the present invention there is provideda telescoping device for inclusion in a riser system, the telescopingdevice comprising:

an inner member telescopingly provided in an outer member;

the inner member being moveable between three configurations in which:

-   -   i) the inner member is locked to the outer member in a        substantially closed configuration such that a substantial        proportion of the inner member is located within the outer        member such that the telescoping device is relatively short;    -   ii) the inner member is locked to the outer member in a        substantially open configuration such that a substantial        proportion of the inner member is located outward of the outer        member such that the telescoping device is relatively long; and    -   iii) the inner member is substantially free to move with respect        to the outer member such that the inner member can telescope in        and out of the outer member;

characterized in that the inner member is adapted to be sealed to theouter member when in at least one of configurations i) and ii) but isarranged to be clear of at least a portion of the outer member when inconfiguration iii).

Preferably, the telescoping device comprises a seal member provided onone of the inner and outer members wherein the seal acts against theother of the inner and outer members to thereby provide a sealtherebetween when the telescoping device is in at least one of theconfigurations i) and ii). Preferably, the seal member is provided onone of the inner and outer members in such a manner that the seal isclear of the at least a portion of the other of the inner and outermembers to thereby not make contact with and thereby not provide a sealwith the other of the inner and outer members when the telescopingdevice is in configuration iii).

Preferably, the telescoping device comprises a selective locking systemto selectively lock the inner member to the said outer member.Typically, the locking system comprises a dog member provided on one ofthe inner and outer members and which is preferably moveable toward andaway from the other of the inner and outer members to make contact withthe other of the inner and outer members to prevent relative movementoccurring therebetween.

Preferably, the dog member is provided on the outer member and ispreferably selectively moveable toward and away from the inner member tomake contact with an outer portion of the inner member to preventrelative movement occurring therebetween. Typically, the outer portionof the inner member comprises a formation formed at least part wayaround the outer circumference of the inner member. Preferably, theinner member comprises two said formations at or toward each end of theinner member.

Typically, one of the inner and outer members is provided with a variedinner or outer circumference such that the seal is prevented from actingagainst the other of the inner and outer members when the seal is at alocation in between the said two formations such that the seal does notact when the telescoping device is in configuration iii).

Typically, the seal is mounted on a portion secured to the outer memberand acts against an inner bore of the inner member. Typically, the sealis located within the bore of the inner member and acts against theinner surface of the bore of the inner member. Typically, the seal issecured within a recess provided on an outer surface of the said portionsecured to the outer member and acts against the inner surface of thebore of the inner member to provide a seal therebetween when thetelescoping device is in one of configurations i) or ii).

Preferably, the dog member is moved radially towards or away from thesaid respective formation by an actuating mechanism which preferablycomprises at least one angled or tapered surface provided on the dogmember and against which the actuating mechanism acts upon in adirection substantially parallel to the longitudinal axis of the risersystem and which results in movement of the dog member in a directionsubstantially perpendicular to the longitudinal axis of the risersystem.

Preferably, the riser system is provided with one or more in-line valveswhich may be selectively opened or closed to respectively permit orprevent flow of fluid through the throughbore of the riser system.Preferably, at least one of said in-line valves is located below thevalved tree member when the one or more valves of the valved tree memberare in sealed fluid communication with the throughbore of the risersystem and more preferably, at least one and typically two in-linevalves are located between the valved tree member and the telescopingdevice. Typically, the telescoping device is located vertically abovethe two inline valves which in turn are located vertically above theflow diverter member and which in turn is located vertically above atleast one in-line valve.

According to a third aspect of the present invention there is provided ariser completion system comprising:

a riser system comprising a lower in-line valve, a flow diverter memberlocated above the lower inline valve and at least one upper in-linevalve located above the flow diverter member and a telescoping devicelocated above the said upper in-line valve to permit compensation forheave; and

a valved tree member suitable for use in the region of a moon pool on afloating vessel, the valved tree member comprising:

-   -   one or more valve members adapted to selectively permit and        prevent flow of fluid therethrough, and    -   one or more moveable stab members adapted to respectively        selectively seal with at least one portion of the flow diverter        member to thereby provide a sealed fluid communication path        between a throughbore of the riser system and the one or more        valve members.

Typically, the flow diverter member comprises:

-   -   a substantially vertical tubular member comprising a throughbore        having a longitudinal axis substantially co-incident with the        longitudinal axis of the riser system at the point at which the        flow diverter member is included in the riser system; and    -   a cross tubular member having a throughbore arranged with its        longitudinal axis substantially perpendicular to the        longitudinal axis of the substantially vertical tubular member;    -   wherein, a lower end of the substantially vertical tubular        member is coupled to a lower portion of the riser system such        that, in use, fluid passing through the lower portion of the        riser system is arranged to enter the throughbore of the lower        end of the substantially vertical tubular member in a fluid        tight manner;    -   an upper end of the substantially vertical tubular member is        coupled to an upper portion of the riser system such that, in        use, fluid passing through the upper end of the substantially        vertical tubular member is arranged to enter the upper portion        of the riser system in a fluid tight manner;    -   and wherein the throughbore of the cross tubular member is in        fluid communication with the throughbore of the substantially        vertical tubular member such that, in use, fluid produced from        the lower portion of the riser system is permitted to flow        through the end(s) of the cross tubular member and/or the upper        end of the substantially vertical tubular member depending upon        the configuration of valves attached thereto.

According to the present invention there is further provided a method ofcompleting a riser installation comprising the steps of:

i) lowering a riser system from a vessel at the surface of a body ofwater to or in close proximity to the surface at the bottom of the bodyof water;

ii) connecting a lower inline valve toward an upper end of the risersystem;

iii) connecting a flow diverter member above the said lower inline valvein the riser system;

iv) connecting at least one upper inline valve above the said flowdiverter member in the riser system;

v) connecting a telescoping member above the said upper inline valve inthe riser system;

vi) connecting the lower end of the riser system to wellhead equipmentprovided at the head of a well;

vii) providing a valved tree member suitable for use in the region of amoon pool on the vessel, the valved tree member comprising one or morevalve members adapted to selectively permit and prevent flow of fluidtherethrough, and one or more moveable stab members wherein the risersystem is run into the sea through a throughbore of the valved treemember;

viii) aligning the T-piece with the valved tree member and coupling theflow diverter member and moving the said one or more stab members torespectively seal with at least one portion of the flow diverter memberto thereby provide a sealed fluid communication path between athroughbore of the riser system and the one or more valve members;

wherein the flow of fluid produced from the upper end of the risersystem is capable of being selectively diverted from flowing up throughthe upper end of the riser system and instead is capable of beingselectively diverted through the said one of more stab members andthrough the said one or more valves of the valved tree member.

In the description that follows, like parts are marked throughout thespecification and drawings with the same reference numerals,respectively. The drawings are not necessarily to scale. Certainfeatures of the invention may be shown exaggerated in scale or insomewhat schematic form, and some details of conventional elements maynot be shown in the interest of clarity and conciseness. The presentinvention is susceptible to embodiments of different forms. There areshown in the drawings, and herein will be described in detail, specificembodiments of the present invention with the understanding that thepresent disclosure is to be considered an exemplification of theprinciples of the invention, and is not intended to limit the inventionto that illustrated and described herein. It is to be fully recognizedthat the different teachings of the embodiments discussed below may beemployed separately or in any suitable combination to produce thedesired results.

The following definitions will be followed in the specification. As usedherein, the term “riser” refers to a riser string coupled to a wellheadat the head of a wellbore or borehole being provided or drilled in amanner known to those skilled in the art. Reference to up or down willbe made for purposes of description with the terms “above”, “up”,“upward”, “upper”, or “upstream” meaning away from the bottom of thebody of water along the longitudinal axis of the riser toward thesurface of the body of water and “below”, “down”, “downward”, “lower”,or “downstream” meaning toward the bottom of the body of water along thelongitudinal axis of the riser and away from the surface and deeper intothe body of water toward the wellhead.

The various aspects of the present invention can be practiced alone orin combination with one or more of the other aspects, as will beappreciated by those skilled in the relevant arts. The various aspectsof the invention can optionally be provided in combination with one ormore of the optional features of the other aspects of the invention.Also, optional features described in relation to one embodiment cantypically be combined alone or together with other features in differentembodiments of the invention. Additionally, any feature disclosed in thespecification can be combined alone or collectively with other featuresin the specification to form an invention.

Various embodiments and aspects of the invention will now be describedin detail with reference to the accompanying figures. Still otheraspects, features, and advantages of the present invention are readilyapparent from the entire description thereof, including the figures,which illustrates a number of exemplary embodiments and aspects andimplementations. The invention is also capable of other and differentembodiments and aspects, and its several details can be modified invarious respects, all without departing from the spirit and scope of thepresent invention.

Any discussion of documents, acts, materials, devices, articles and thelike is included in the specification solely for the purpose ofproviding a context for the present invention. It is not suggested orrepresented that any or all of these matters formed part of the priorart base or were common general knowledge in the field relevant to thepresent invention.

Accordingly, the drawings and descriptions are to be regarded asillustrative in nature, and not as restrictive. Furthermore, theterminology and phraseology used herein is solely used for descriptivepurposes and should not be construed as limiting in scope. Language suchas “including”, “comprising”, “having”, “containing” or “involving” andvariations thereof, is intended to be broad and encompass the subjectmatter listed thereafter, equivalents, and additional subject matter notrecited, and is not intended to exclude other additives, components,integers or steps. In this disclosure, whenever a composition, anelement or a group of elements is preceded with the transitional phrase“comprising”, it is understood that we also contemplate the samecomposition, element or group of elements with transitional phrases“consisting essentially of”, “consisting”, “selected from the group ofconsisting of”, “including”, or “is” preceding the recitation of thecomposition, element or group of elements and vice versa. In thisdisclosure, the words “typically” or “optionally” are to be understoodas being intended to indicate optional or non-essential features of theinvention which are present in certain examples but which can be omittedin others without departing from the scope of the invention.

All numerical values in this disclosure are understood as being modifiedby “about”. All singular forms of elements, or any other componentsdescribed herein including (without limitations) components of the risersystem are understood to include plural forms thereof and vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way ofexample only, with reference to the accompanying drawings, in which:

FIG. 1A is a schematic overview (not to scale) of the initial stage ofthe installation of a riser system from a drill ship, utilizing a moonpool surface tree in accordance with a first aspect of the presentinvention;

FIG. 1B is a more detailed few of a portion of FIG. 1A, where FIG. 1Bshows the christmas tree sitting on the mud line or subsea surface(bottom of the sea);

FIG. 2A shows a next stage of the installation of the riser system,where the EDP and LRP have been connected to the lower end of the risersystem and have been lowered into the sea through the moon pool of thedrill ship;

FIG. 2B is a more detailed close up view of the LRP, EDP and lowerportion of the riser system;

FIG. 2C is a close up more detailed view of one of the screw threadedconnections that makes up the separate lengths of flexible riser tubularor flow line into the connected flexible riser system;

FIG. 3A is a schematic side view of the next stage of installation ofthe riser system in accordance with various aspects of the presentinvention where the riser system has continued to be lowered into thesea down toward the christmas tree and FIG. 3A also shows a telescopicjoint in accordance with a second aspect of the present invention at theupper end of the riser system;

FIG. 3B shows a more detailed schematic side view of the upper end ofthe riser system (with the lower end of the riser system having beenomitted for clarity) being lowered through the drill floor and through adiverter housing of the riser system, where the moon pool surface treeis shown as still being coupled to the diverter housing;

FIG. 3C is a much more detailed and closer schematic side view of detailA of FIG. 3B showing a set of dogs used to couple an active support ringof the moon pool surface tree to the diverter housing;

FIG. 4A is a close up schematic side view of the telescopic joint and aseries of in-line valves connected thereto being lowered through thediverter housing and also shows that the active support ring of the moonpool surface tree has been disconnected from the diverter housing, wherethe moon pool surface tree is supported by wire tensioners from thedrill floor;

FIG. 4B is a closer up more detailed schematic side view of detail A ofFIG. 4A showing the dogs that were used to connect the active supportring to the diverter housing having been retracted to allow for thedisconnection of the active support ring from the diverter housing;

FIG. 5A shows a schematic side view (not to scale) of the next stage ofthe installation of the riser system in accordance with various aspectsof the present invention, where the LRP and the EDP have been loweredinto connection with the christmas tree and therefore the drill shipmust be able to heave with respect to the riser system;

FIG. 5B is a schematic but closer up and more detailed side view of aportion of the upper section of the riser system of FIG. 5A;

FIG. 5C is a more detailed closer up schematic side view of the upperend of the riser system being shown in cross-section, where a combinedlanding ring and flow diverter piece is included in the riser system inaccordance with a third aspect of the present invention and has beenlocated within the moon pool surface tree and has landed out thereinsuch that the weight of the riser system is transferred to the moon poolsurface tree and therefore to the drill ship via the tensioning wireswhich can compensate for the heave of the drill ship relative to theriser system;

FIG. 5D shows a much more detailed close up sectional side view of thedetail area “A” of FIG. 5C and therefore shows the combined landing ringand flow diverter piece having landed out on the load shoulder of themoon pool surface tree;

FIG. 5E shows a cross-sectional perspective view of the moon poolsurface tree with its active support ring and where the combined landingring and flow diverter piece of the riser system has landed out on theload shoulder of the moon pool surface tree;

FIG. 5F is another version of the cross-sectional perspective view ofthe moon pool surface tree of FIG. 5E;

FIG. 6A is a schematic side view (not to scale) of the next stage of theinstallation of the riser system in accordance with various aspects ofthe present invention, where the upper most riser package equipment canbe safely coupled and un-coupled to the upper end of the universalconnection of the telescopic joint in a safe manner because thetelescopic joint can telescope in and out of the other lower half of thetelescopic joint and therefore the upper end of the telescopic joint canremain stationery with respect to the drill ship and therefore providesfor safer connection to the upper most riser package equipment such asthe coiled tubing unit, lubricator or surface tree, whilst thehydrocarbon product can be diverted through the moon pool surface treeand out through either or both side ball valves, in accordance withvarious aspects of the present invention, once valve stabs have beenmoved into and locked with respect to the inner bore of the sideapertures of the combined landing ring and flow diverter piece (as shownin FIG. 6F);

FIG. 6B shows the moon pool surface tree with the telescopic joint ofFIG. 6A coupled in the riser string in a fully stroked in/running inconfiguration;

FIG. 6C is a cross-sectional schematic view of the moon pool surfacetree of FIG. 6A but now in an operating configuration where it isdiverting hydrocarbon production to the side valves attached thereto andis therefore shown in an operating configuration;

FIG. 6D is a cross-sectional schematic view showing the moon poolsurface tree in more detail in the configuration shown in FIG. 6C;

FIG. 6E is a more detailed cross-sectional schematic view of the moonpool surface tree in the same configuration as FIG. 6D;

FIG. 6F is a more detailed and closer up schematic cross-sectional viewof the detail area “A” of FIG. 6C;

FIG. 6G is a closer up more detailed cross-sectional schematic view ofthe telescopic joint when in the running in configuration shown in FIG.6C;

FIG. 6H is a closer up more detailed view of the detail area “A” of FIG.6G of the telescopic joint when in the running in configuration, whereFIG. 6H shows the dogs of the telescopic joint in the lockedconfiguration thereby locking the telescopic joint in the configurationshown in FIG. 6G;

FIG. 7A shows the telescopic joint of FIG. 6G as having been unlockedand being free to stroke;

FIG. 7B is a closer up more detailed view of detail area “A” of thetelescopic joint of FIG. 7A, where FIG. 7B shows the locking dogs in theunlocked configuration;

FIG. 8A is a perspective view of the moon pool surface tree with thetelescopic joint of FIG. 6A attached to the upper end of the section ofthe riser system string that passes through the moon pool surface tree,where the telescopic joint is now shown in the stroked out configurationor open configuration or operating configuration;

FIG. 8B shows a cross-sectional schematic view of the telescopic jointwhen in the configuration shown in FIG. 8A;

FIG. 8C is a cross-sectional schematic view of detail area “A” showingthe locking dogs in the locked configuration therefore locking thetelescopic joint in the open configuration;

FIG. 9A is a perspective side view of the moon pool surface tree of FIG.6A and in particular showing hydraulic stabs for valve/connector supply;and

FIG. 9B shows a perspective view from below of the moon pool surfacetree showing the hydraulic stabs of FIG. 9A being presented intoalignment with their respective aperture formed in the moon pool surfacetree.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a riser installation system 10 which is typically locatedon a sea going vessel 8 (not shown) such as a drill ship or floatingproduction facility or other suitably arranged sea going vessel 8 (onlypartially shown in the Figures) where the vessel 8 comprises a drillfloor 12 and a moon pool 14 located immediately below the drill floor12, where the moon pool 14 comprises an opening in the bottom of the seagoing vessel and through which a riser system 35 and other equipment tobe installed on the sea bed in the general location below the sea goingvessel 8 can be lowered through.

As can be seen in FIGS. 1A and 1 n more detail in FIG. 1B, a christmastree 20 has already been lowered from the sea going vessel 8 (or fromanother sea going vessel not shown)) through the moon pool 14 and intothe water at the water line 16 and further lowered all the way to thesea bed surface or the mud line 18 which may be many thousands of feetand in FIG. 1 the distance between mud line 18 and the drill floor 12 inthe example shown is in the region of 10,000 feet.

FIG. 1A also shows the first stage or start of the installation of theriser system 35, where the riser system 35 also comprises further safetyequipment in the form of an emergency disconnect package and a lowerriser package 22, 24 and which are sitting on a moon pool trolley 26,awaiting to be picked up such that the moon pool trolley 26 can beremoved thereby opening the moon pool 14 such that the EDP 22 and theLRP 24 can be lowered through the moon pool 14 into the water line 16and down to the subsea installation location on top of the christmastree 20, where the lower end of the LRP 24 will be securely connected tothe tree cap 28 located at the upper end of the christmas tree 20.

The riser system 35 further comprises a riser string 32 and a riserrunning tool 30, where the upper end of the EDP 22 is picked up byrunning the riser running tool 30 being provided at the lower end of thestring 32 of flexible riser pipe 32T connected end 32P to end 32B bysuitable connections such as a Merlin™ connection offered by Oil StatesIndustries (UK) Limited of Aberdeen, UK (only a very short portion ofthe riser string 32 is shown in FIG. 1A). The riser running tool 30comprises a swivel joint 34 at its lower end being further connected toa weak link 36 and further being coupled to a flex joint 38, where theswivel joint 34 permits rotation of its lower end relative to its upperend and where the weak link 36 can be sheared apart if needs be toseparate the riser string 32 from the tools located below the weak link36 and where the flex joint 38 permits some flexing to allow a degree ofmovement to occur between the riser string 32 and the EDP 22 as and whennecessary. The riser running tool 30 is lowered through the drill floor12 through an automated Merlin™ connector make up tool 40 and which tool40 will be used to connect further lengths of the riser pipe 32Ttogether and is further run through a diverter housing 42 and a moonpool surface tree 50 in accordance with the present invention, where themoon pool surface tree 50 is, when in the configuration shown in FIG.1A, securely coupled to the diverter housing 42.

The next stage of installation of the riser system 35 as can be seen inFIG. 2A, where the riser running tool 30 has, along with the flex joint38, the weak link 36 and the swivel joint 34, been lowered (on the lowerend of the riser string 32) through firstly the make up tool 40 andtherefore through the drill floor 12 and then through the diverterhousing 42 and through a bore 51 (shown in FIG. 3B) provided in the moonpool surface tree 50 until the flex joint 38 is securely coupled to theEDP 22 and thus the LRP 24 and the riser string 32 is then lifted upsuch that the moon pool trolley 26 can then be removed and the riserstring 32 can then be lowered with the rest of the equipment 30, 22, 24now coupled thereto through the moon pool 14 and into the water throughthe water line 16. As can further be seen in FIG. 2A, a pair ofumbilical lines 52A, 52B have a lower end which is coupled to the upperend of the EDP 22 where the umbilicals 52A, 52B can be payed out from arespective reel 54A, 54B via a respective sheave 56A, 56B and can beclamped to the outer surface of the riser string 32 at spaced apartlocations by means of an umbilical clamp 58, where the umbilicals 52A,52B can be used to supply power and/or data via an electrical lineand/or can supply fluid such as hydraulic fluid via a hydraulicumbilical 52A, 52B.

As can be seen in FIGS. 2B and 2C, the riser string 32 is made up ofdistinct lengths of flexible riser tubing or pipe 32T having a pin end32P provided at an upper end thereof and a box end 32B provided at alower end thereof where the lower end 32B is coupled to a pin end 32P ofthe next flexible tubing 32T and a preferred pin 32P and box 32Bcomprise the Merlin™ connector offered by Oil States Industries (UK)Limited of Aberdeen, United Kingdom.

Additional lengths of flexible riser tubing 32T continue to be made upby the make up tool 40 into the riser string 32 at the upper end thereofsuch that the LRP 24 and EDP 22 continue to be lowered on the riserstring 32 down toward the christmas tree 20 as shown in FIG. 3A untilsuch a time that the LRP 24 is located just above the christmas tree 20as shown in FIG. 3A. At this point, an upper riser package 48 (shown inFIG. 3B) is coupled to the upper end of the riser string 32, where theupper riser package 48 comprises a telescopic joint 60 in accordancewith the second aspect of the present invention at its upper most end,the details of which will be discussed subsequently, where the lower endof the telescopic joint 60 is coupled to the upper end of an upperin-line ball valve 62 and which in turn is coupled via its lower end tothe upper end of a middle in-line ball valve 64 and which in turn iscoupled via its lower end to the upper end of a combined landing ringand flow diverter piece 66 and which in turn is coupled at its lower endto the upper end of a lower in-line ball valve 68 and which in turn iscoupled at its lower end to the upper end of the riser string 32. Itshould be noted that the riser string 32 is omitted from FIG. 3B forclarity purposes.

The combined landing ring and flow diverter piece 66 preferablycomprises a vertically arranged main body in the form of a tubular orpipe 66 having an upper 66U and a lower 66L half connected into theriser string 32 and forming part of it and having its longitudinalthroughbore 33, where the upper half 66U and lower half 66L are formedintegral with or are securely and sealingly coupled to a landing ring 65and which has a lower shoulder 72 formed or provided around its outerlower most circumference (the use of which will be detailedsubsequently) and which also comprises a horizontally arrangedthroughbore 67 which perpendicularly intersects the main verticallyarranged longitudinal throughbore 33 and through which produced fluidsfrom the subsea well can be diverted through into stabs 76A, 76B whenconnected thereto (as will be described subsequently). A key (not shown)and groove (not shown) are provided to ensure the correct rotationalalignment occurs between the combined landing ring and flow diverter 66and more particularly between the throughbore 67 and the stabs 76A, 76Bduring seating of the landing ring 66 against an upwardly directedshoulder 74 (as will be described in more detail subsequently). Theskilled reader will understand that the annular ring shaped landing ring65 with a horizontally arranged cross intersecting throughbore 67 couldbe replaced by a pair of laterally arranged tubular output ports whichprovide the same horizontally arranged cross intersecting throughbore 67but the annular ring shaped landing ring 65 has the advantage ofspreading the seating load 360° around its whole circumference due tothe seating contact between the respective shoulders 72 and 74 as willbe described in more detail subsequently.

As can be seen in FIGS. 3A and 3B, the moon pool surface tree 50 is atthis point still securely coupled to the diverter housing 42 via anActive Support Ring (ASR) 44 (an example of which is offered by OilStates Industries (UK) Limited of Aberdeen, United Kingdom). The ASR 44dynamically compensates for any torsional movement between the vessel 8and the riser system 35 via geared motorized connection between an ASRouter ring 44O (see FIGS. 3C and 5E) (which is fixed to the vessel 8)and an ASR main body 44B (which will be fixed to the riser system 35 aswill be described subsequently). A lower set of dogs 52L projectradially inwardly from the ASR outer ring 44O into a recess providedaround the outer surface of an ASR bearing surface 44S (see FIG. 5E)(and where the moon pool surface tree 50 is secured to the ASR main body44B and where motors provided on the ASR main body 44B can rotate theASR main body 44B with respect to the ASR bearing surface 44S tocompensate for torsion therebetween) and an upper set of dogs 52Uproject radially inwardly from the ASR outer ring 44O into a recessprovided around the lower end of the diverter housing 42 such that whenboth sets of dogs 52L, 52U project radially inwardly into theirrespective recess, the moon pool surface tree 50 is secured to thediverter housing 42.

However, just prior to the moment when the upper riser package 48 startspassing through the bore 51 of the moon pool surface tree 50, the upperset of dogs 52U are retracted from their recess in the diverter housing42 such that the upper dogs 52U are released from the diverter housing42 and therefore the moon pool surface tree 50 is disconnected from thediverter housing 42. Instead, the weight of the ASR 44 and thus the moonpool surface tree 50 is taken up by at least two and preferably at leastthree (not shown) tension wires 82A, 82B which are payed out fromrespective tension wire reels 84A, 84B secured to the vessel 8 and thisstage of the riser installation method is shown in FIG. 4A.

The weight of the moon pool surface tree 50 is thus taken up by the ASR44 and thus the tension wire reels 84A, 84B and the moon pool surfacetree 50 and ASR 44 are lowered a short distance away from the lower endof the diverter housing 42. The upper riser package 48 is then loweredthrough the diverter housing 42 and through the bore 51 of the moon poolsurface tree 50 until a lower shoulder 72 of the combined landingring/flow diverter piece 66 makes contact with and therefore buttsagainst an upwardly directed shoulder 74 provided around the inner bore51 of the moon pool surface tree 50 such that at least a proportion ofand possibly up to the whole weight of the riser string is taken on theupwardly directed load shoulder 74 and therefore by the tension wires82A, 82B and the tension wire reel 84A, 84B and at this point the riserstring is in the running in configuration shown in FIGS. 5A, 5B, 5C, 5D,5E and 5F and this configuration can be regarded as the last stage ofthe running in of the riser string 32.

The LRP 24 is secured to the tree cap 28 and then the combined landingring/flow diverter piece 66 and thus the rest of the upper riser package48 and the riser string 32 indeed the whole riser system 35 can besecured to the moon pool surface tree 50 by actuating stabs 76A, 76Blocated within laterally arranged flanged pipes 90A, 90B mountedhorizontally on each side of the moon pool surface tree 50 such that thethroughbores of the flanged pipes 90A, 90B are horizontally aligned withone another and are arranged perpendicularly to the longitudinal andvertically arranged throughbore 51 of the moon pool surface tree 50. Thestabs 76A, 76B are arranged such that they can be actuated to moveradially inwardly (with respect to the longitudinal vertically arrangedthroughbore 51) from being wholly located within the throughbore of theflanged pipes 90A, 90B to respectively project at least partially intothe horizontally arranged throughbore 67 of the laterally projectingside ports 69A, 69B of the combined landing ring/flow diverter piece 66.The radially inner most ends of the stabs 76A, 76B are provided withsuitable seals such as O-ring seals 78A, 78B around their outercircumference such that the respective throughbore 76AT; 76BT of thestabs 76A, 76B is sealed by the seals 78A, 78B with respect to thethroughbore 67 of the combined landing ring/flow diverter piece 66.Accordingly, the stabs 76A, 76B have a dual function of not onlyphysically locking the combined landing ring/flow diverter piece 66 andthus the riser string 32 to the moon pool surface tree 50 but alsoprovide a seal between:

-   -   i) the inner throughbore 51 of the moon pool surface tree 50        (and indeed the outer environment); and    -   ii) the inner throughbore 33 of the riser string 32    -   such that the respective throughbore 76AT; 76BT of the stabs        76A, 76B is in sealed fluid communication with the throughbore        67 of the combined landing ring/flow diverter piece 66 and thus        is in sealed fluid communication with the throughbore 33 of the        riser string 33. The riser string 32 and moon pool surface tree        50 are now in the operating position as shown in FIG. 6A through        FIG. 6F.

At this point the operator now has the option of diverting fluid locatedin or flowing through the throughbore 33 of the riser string 32 locatedbelow the middle ball valve 64 out of the throughbore 33, through thethroughbore 76B and through the lateral ball valves 70A, 70B located onthe moon pool surface tree 50 and out of lateral exit ports 71A, 71Binto e.g. conduits or hoses (not shown) and onto further pressurizedfluid containment equipment (not shown) which may be located below thedrill floor 12 by ensuring that upper ball valve 62 and middle ballvalve 64 are closed such that fluid cannot flow through the throughbore33 up through the middle ball valve 64 or upper ball valve 62. It shouldbe noted that only one upper or middle ball valve 62, 64 is required buttwo are provided to ensure that there is redundancy in case one is stuckor malfunctions and cannot close. Accordingly, the operator can conducta well test via the lateral ball valves 70A, 70B of the moonpool surfacetree 50.

Consequently, the moon pool surface tree 50 provides the great advantagethat, in combination with the combined landing ring/flow diverter piece66, and the valves 62, 64, 68 run therewith, the potentially highlypressurized fluid such as produced hydrocarbons located within thethroughbore 33 below the moon pool surface tree 50 can be safelycontrolled, thus allowing the operator to perform a well test or conductwork on the riser system 35 and/or riser string 32 located above themoon pool surface tree 50 and more particularly located above the upperball valve 62. For example, the final required equipment 100, 102, 104can be safely installed to the upper end of the universal connection 61provided at the uppermost end of the telescopic joint 60 in a safemanner because the pressurized fluid located within the throughbore 33is all located below the closed upper 62 and middle 64 ball valves andis being safely diverted to said other pressurized fluid containmentequipment.

However, to further increase the safety of connecting that final safetyequipment such as a surface tree 100, lubricator 102 and/or coiledtubing unit 104, the telescopic joint 60 is adapted to be able to strokeout from the fully stroked in (also referred to as the running inconfiguration) configuration shown in FIG. 6B and FIG. 6C andparticularly in FIG. 6G to a free to stroke configuration shown in FIG.7A to allow the universal joint 61 at its upper end to remain staticwith respect to the drill floor 12 in order to compensate for the heaveof the vessel 8 relative to the riser system 35 and onto a fully openconfiguration as shown in FIG. 8B, as will now be described in detail.

The telescopic joint 60 in accordance with the second aspect of thepresent invention comprises an outer barrel 110 which is secured at itslower end 110L to the upper end of the upper ball valve 62 such that thethroughbore 109 of the telescopic joint 60 is in sealed fluidcommunication with the throughbore 33 of the riser string 32 and therest of the riser system 35 (assuming that the upper 62 and middle 64in-line ball joints are open). The inner bore 109 comprises a protrudingtubular end 111 which projects upwardly and to which is secured (bymeans of a suitable fixing means such as welding or a sealed screwthread or other suitable fixing means) to the lower end of an internalsealing tube 115 at its lower end 115L. It should be noted that theinternal sealing tube 115 is preferably a separate component from therest of the outer barrel 110 to aid manufacture and installation andalso to aid repair but it could be that the internal sealing tube 115 isa one piece unit integral with the outer barrel 110. The outer diameterof the internal sealing tube 115 forms an annulus 116 with the innerbore of the rest of the outer barrel 110 and an inner barrel 120 islocated in that annulus 116 (when in the fully stroked in configurationas shown in FIG. 6B) where the inner barrel 120 comprises the universaljoint 61 at its upper end and the inner barrel 120 is arrange totelescope in and out in a stroking manner within the outer barrel 110when it is permitted to do so as will now be described.

The inner barrel 120 is provided with a formation in the form of anupper dog ring 126U provided towards its upper end on its outer surfaceand is further provided with a lower dog ring 126L provided toward or atits lower end again on its outer surface. Two or more concentricallyspaced apart dogs 124 are provided around the outer circumference of theinner barrel 120 and are located in a suitably sized recess within theouter barrel 110 where the dogs 124 can be forced radially inwardlytoward the outer surface of the inner barrel 120 by means of a cam ring128 which can be forced (when actuated to do so by actuating cylinders130) in a downwards direction to act on a tapered outer face 124T of thedogs 124 to force the dogs 124 radially inwardly against the outersurface of the inner barrel 120 and in particular to trap the upper dogring 126U or lower dog ring 126L as appropriate within a recess 124Rformed on the inner surface of the dogs 124.

Consequently, when the respective dog ring 126U, 126L is trapped withinthe recess 124R, the inner barrel 120 is locked with respect to theouter barrel 110. Moreover, when the upper dog ring 126U is trappedwithin the recess 124R (as shown in FIG. 6G and FIG. 6H), the telescopicjoint 60 is in the fully stroked in or closed position as shown in FIG.6G. In this position, seals 117 provided on the outer surfaceconcentrically around the upper end of the internal sealing tube 115 aretypically slightly spaced apart from the inner bore at the upper end ofthe inner barrel 120 such that there is no seal against the inner boreat the upper end of the inner barrel 120 when in the fully stroked in orclosed position as shown in FIG. 69 because there won't be any producedhydrocarbons flowing through the throughbore 109 when in thatconfiguration.

When the operator decides to allow the inner barrel 120 to stroke out ofthe inner barrel 110, he actuates the cylinders 130 to move the cam ring128 upwards which in turn permits the dogs 124 to relax or move radiallyoutwardly away from the upper dog ring 126U such that the inner barrel120 can now move upwards with respect to the outer barrel 110 as shownin FIG. 7A.

Importantly, the inner bore of the inner barrel 120 is provided with aslightly enlarged inner bore 121 along its upper and its middle sectionsuch that the slightly enlarged inner bore 121 clears the pair of seals117 such that the slightly enlarged inner bore 121 is not sealed withrespect to the outer surface of the internal sealing tube 115 and inuse, this has the advantage that the seals 117 will not be worn away bythe telescoping action of the inner barrel 120 moving with respect tothe internal sealing tube 115 and the outer barrel 110. Because of thisfeature, the operator will ensure that when the inner barrel 120 is inthe closed or fully stroked in configuration shown in FIG. 69 or when inthe free to stroke configuration as shown in FIG. 7A, the upper 62and/or middle 64 ball valves are in the closed position such that nofluid can flow through the throughbore 33 of the riser system 35 abovethe upper ball valve 62.

The telescopic joint 60 is shown in the fully stroked out or fully openposition in FIG. 8A and FIG. 8B and is thus in the operating positionwhere the seals are now in sealed abutment against the lower end of theinner bore of the inner barrel 120 and as shown most clearly in FIG. 8Cthe recess 124R traps the lower dog ring 126L due to the dogs 124 beingforced radially inwardly by the cam ring 128. Thus, the operator cansafely produce hydrocarbons up the throughbore 33 of the riser system 35and up throughbore 109 of the telescopic joint 60 by opening up theupper 62 and middle 64 ball valves and ensuring lower ball valve 68 isopen and also ensuring lateral ball valves 70A, 70B are closed.Compensation for heave of the vessel 8 relative to the riser system 35whilst the telescopic joint 60 is locked in the fully stroked outposition of FIG. 8A (or whilst locked in the fully stroked in positionof FIG. 6G) is provided for by an additional compensation system (notshown) located above the drill floor 12 at the upper most end of theriser system 35.

FIG. 9A shows two hydraulic valve stabs 140 being provided through theside wall of the moon pool surface tree 50.

The hydraulic valve stabs 140 provide a suitable connection such as tosupply electrical power or supply of pneumatic or hydraulic fluid to thevarious ball valves 62, 64, 68, 70 and also provide for hydraulicconnection for operation of the actuating cylinders 130 such thatelectric power and/or hydraulic fluid can be delivered to the variousvalves 62, 64, 68, 70 and also the actuating cylinder 130 to operate therespective valves 62, 64, 68, 70 and/or the telescopic jointlocking/unlocking system and therefore all power and/or hydraulicsupplies to the various valves 62, 64, 68, 70 and the actuating cylinder130 can be connected up before the equipment is run and this eliminatesthe need for man-riding during set up thereby greatly improving safety.Only two hydraulic valve stabs 140 are shown in FIG. 9A where the othertwo are located around the other side of the moon pool surface tree 50.The four stabs 140 can provide eight hydraulic lines. All four hydraulicstabs 130 can be seen in FIG. 9H. The skilled reader will understandthat fewer or more stabs 140 can be provided through the sidewall of themoon pool surface tree 5 as required.

Accordingly, embodiments of the present invention described hereinprovide the ability to remotely operate the various valves 62, 64, 68,70 and/or the actuating cylinder 130 (the remote operation possiblybeing conducted a relatively short or a relatively long distance awayfrom the relevant equipment 62, 64, 68, 70, 130 either on or off thevessel 8) and also provide the advantage of permitting remotedisconnection of the equipment on the drill floor 12 to the riser system35 and also provide the great advantage of allowing for the halting orthe diversion of production flow to relevant equipment on or below thedrill floor 12.

These advantages individually or combine to permit work to be safelycarried out on the top level equipment 100, 102, 104 on the drill floorwithout the hazards associated with sea movement.

Consequently, the various embodiments described herein provide numeroussignificant safety and operational advantages over conventional risersystems.

Modifications or improvements may be made to the embodiments describedherein without departing from the scope of the invention.

1. A valved tree member for inclusion in a riser system and suitable foruse in the region of a moon pool on a floating vessel, the valved treemember comprising: one or more valve members adapted to selectivelypermit and prevent flow of fluid therethrough, and one or more moveablestab members adapted to respectively selectively provide a sealed fluidcommunication path between a throughbore of the riser system and the oneor more valve members.
 2. The valved tree member of claim 1, furthercomprising a body member upon which the said one or more valves aremounted, wherein each of the one or more valve members mounted thereoncomprises a longitudinal axis arranged substantially perpendicularly toa longitudinal axis of the riser system at the point at which the valvedtree member is included in the riser system.
 3. The valved tree memberof claim 2, wherein the one or more valve members are connected to thebody member by a tubular coupling having a throughbore.
 4. The valvedtree member of claim 3, wherein the said moveable stab member is locatedwithin the throughbore of the tubular coupling.
 5. The valved treemember of claim 2, wherein the moveable stab member is arranged toselectively engage with a port provided in the riser system.
 6. Thevalved tree member of claim 5, wherein the said moveable stab member isarranged to selectively sealingly engage with the port provided in theriser system.
 7. The valved tree member of claim 6, wherein the port isincluded at a suitable location in the riser system and comprises atleast an aperture through a sidewall of the riser system.
 8. The valvedtree member of claim 7, wherein the said moveable stab member isarranged to selectively move radially inwards toward the longitudinalaxis of the riser system in a direction substantially perpendicular tothe longitudinal axis of the riser system to sealingly engage with theport such that fluid in the throughbore of the riser system is allowedto flow in a sealed manner from the throughbore of the riser systemthrough the moveable stab member and into the said one or more valvesmounted on the valved tree member.
 9. The valved tree member of claim 5,wherein a flow diverter member is included in the riser system, the flowdiverter member comprising a substantially vertical tubular memberhaving a longitudinal axis substantially parallel with the longitudinalaxis of the riser system at a point at which the flow diverter member isincluded in the riser system.
 10. The valved tree member of claim 9,wherein the substantially vertical tubular member has the longitudinalaxis substantially co-incident with the longitudinal axis of the risersystem at the point at which the flow diverter member is included in theriser system.
 11. The valved tree member of claim 9, wherein the flowdiverter member further comprises a cross tubular member.
 12. The valvedtree member of claim 11, wherein the cross tubular member is arrangedwith its longitudinal axis to be substantially perpendicular to thelongitudinal axis of the substantially vertical tubular member.
 13. Thevalved tree member of claim 11, wherein the cross tubular memberprovides the port at each end thereof.
 14. The valved tree member ofclaim 11, wherein the flow diverter member comprises three or more fluidentry/exit points.
 15. The valved tree member of claim 14, wherein theflow diverter member comprises four fluid entry/exit points where twoare provided by each end of the substantially vertical tubular memberand two are provided by each end of the cross tubular member.
 16. Thevalved tree member of claim 11, wherein respective throughbores of thecross tubular member and the substantially vertical tubular memberintersect one another.
 17. The valved tree member of claim 1, whereinthe valved tree member is selectively coupled to a housing memberprovided on the floating vessel.
 18. The valved tree member of claim 17,further comprising a selective locking system configured to selectivelylock the valved tree member to the said housing member of the floatingvessel.
 19. The valved tree member of claim 18, wherein the valved treemember is locked to the said housing member when the riser system isbeing run into the body of water on which the vessel is floating, theriser system being run in through a throughbore of the valved treemember and through the moon pool of the floating vessel.
 20. The valvedtree member of claim 19, wherein once the one or more valves of thevalved tree member are in sealed fluid communication with thethroughbore of the riser system, the selective locking system isunlocked to release the valved tree member from engagement with thehousing member and one or more tension supporting members are providedto support the weight of the valved tree member.
 21. The valved treemember of claim 20, wherein the one or more tension supporting memberspermit relative movement to occur between the valved member which issecured to the riser system and the floating vessel such that the one ormore tension supporting members also bear at least a portion of theweight of the riser system and thereby compensate for relative heavebetween the riser system and the floating vessel.
 22. The valved treemember of claim 21, wherein the relative movement is substantiallyvertical.
 23. A telescoping device for inclusion in a riser system, thetelescoping device comprising: an inner member telescopingly provided inan outer member; the inner member being moveable between threeconfigurations in which: i) the inner member is locked to the outermember in a substantially closed configuration such that a substantialproportion of the inner member is located within the outer member suchthat the telescoping device is relatively short; ii) the inner member islocked to the outer member in a substantially open configuration suchthat a substantial proportion of the inner member is located outwith ofthe outer member such that the telescoping device is relatively long;and iii) the inner member is substantially free to move with respect tothe outer member such that the inner member can telescope in and out ofthe outer member, wherein the inner member is sealed to the outer memberwhen in at least one of configurations i) and ii), wherein the innermember is clear of at least a portion of the outer member when inconfiguration iii).
 24. The telescoping device of claim 23, wherein thetelescoping device comprises a seal member provided on one of the innerand outer members wherein the seal acts against the other of the innerand outer members to thereby provide a seal there between when thetelescoping device is in at least one of the configurations i) and ii).25. The telescoping device of claim 24, wherein the seal member isprovided on one of the inner and outer members in such a manner that theseal is clear of the at least a portion of the other of the inner andouter members to thereby not make contact with and thereby not provide aseal with the other of the inner and outer members when the telescopingdevice is in configuration iii).
 26. The telescoping device of claim 24,wherein the telescoping device comprises a selective locking system toselectively lock the inner member to the said outer member.
 27. Thetelescoping device of claim 26, wherein the locking system comprises adog member provided on one of the inner and outer members, the dog beingmoveable toward and away from the other of the inner and outer membersto make contact with the other of the inner and outer members to preventrelative movement occurring therebetween.
 28. The telescoping device ofclaim 27, wherein the dog member is provided on the outer member and isselectively moveable toward and away from the inner member to makecontact with an outer portion of the inner member to prevent relativemovement occurring therebetween.
 29. The telescoping device of claim 27,wherein the outer portion of the inner member comprises a formationformed at least part way around the outer circumference of the innermember.
 30. The telescoping device of claim 29, wherein the inner membercomprises two said formations at or toward each end of the inner member.31. The telescoping device of claim 30, wherein one of the inner andouter members is provided with a varied inner or outer circumferencesuch that the seal is prevented from acting against the other of theinner and outer members when the seal is at a location in between thetwo formations such that the seal does not act when the telescopingdevice is in configuration iii).
 32. The telescoping device of claim 29,wherein the dog member is moved radially towards or away from therespective formation by an actuating mechanism.
 33. The telescopingdevice of claim 32, wherein the actuating mechanism comprises at leastone angled or tapered surface provided on the dog member and againstwhich the actuating mechanism acts upon in a direction substantiallyparallel to a longitudinal axis of the riser system and which results inmovement of the dog member in a direction substantially perpendicular tothe longitudinal axis of the riser system.
 34. The telescoping device ofclaim 24, wherein the seal is mounted on a portion secured to the outermember and acts against an inner bore of the inner member.
 35. Thetelescoping device of claim 34, wherein the seal is located within thebore of the inner member and acts against the inner surface of the boreof the inner member.
 36. The telescoping device of claim 35, wherein theseal is secured within a recess provided on an outer surface of the saidportion secured to the outer member and acts against the inner surfaceof the bore of the inner member to provide a seal therebetween when thetelescoping device is in one of configurations i) or ii).
 37. A risercompletion system comprising: a riser system comprising: a lower in-linevalve, a flow diverter member located above the lower inline valve andat least one upper in-line valve located above the flow diverter member,and a telescoping device located above the said upper in-line valve topermit compensation for heave; and a valved tree member suitable for usein the region of a moon pool on a floating vessel, the valved treemember comprising: one or more valve members adapted to selectivelypermit and prevent flow of fluid therethrough, and one or more moveablestab members adapted to respectively selectively seal with at least oneportion of the flow diverter member to thereby provide a sealed fluidcommunication path between a throughbore of the riser system and the oneor more valve members.
 38. The riser completion system of claim 39,wherein the lower and upper in-line valves are adapted to be selectivelyopened or closed to respectively permit or prevent flow of fluid throughthe throughbore of the riser system.
 39. The riser completion system ofclaim 38, wherein the lower in-line valves is located below the valvedtree member when the one or more valves of the valved tree member are insealed fluid communication with the throughbore of the riser system. 40.The riser completion system of claim 38, wherein the upper in-line valveis located between the valved tree member and the telescoping device.41. The riser completion system of claim 40, wherein two upper in-linevalves are provided.
 42. The riser completion system of claim 37,wherein the valved tree member further comprises a body member uponwhich the said one or more valves are mounted, wherein each of the oneor more valve members mounted thereon comprises a longitudinal axisarranged substantially perpendicularly to a longitudinal axis of theriser system at the point at which the valved tree member is included inthe riser system.
 43. The riser completion system of claim 37, whereinthe telescoping device comprises: an inner member telescopingly providedin an outer member; the inner member being moveable between threeconfigurations in which: i) the inner member is locked to the outermember in a substantially closed configuration such that a substantialproportion of the inner member is located within the outer member suchthat the telescoping device is relatively short; ii) the inner member islocked to the outer member in a substantially open configuration suchthat a substantial proportion of the inner member is located outwith ofthe outer member such that the telescoping device is relatively long;and iii) the inner member is substantially free to move with respect tothe outer member such that the inner member can telescope in and out ofthe outer member, wherein the inner member is sealed to the outer memberwhen in at least one of configurations i) and ii), wherein the innermember is clear of at least a portion of the outer member when inconfiguration iii).
 44. The riser completion system of claim 37, whereinthe flow diverter member comprises: a substantially vertical tubularmember comprising a throughbore having a longitudinal axis substantiallyco-incident with the longitudinal axis of the riser system at the pointat which the flow diverter member is included in the riser system; and across tubular member having a throughbore arranged with its longitudinalaxis substantially perpendicular to the longitudinal axis of thesubstantially vertical tubular member; wherein a lower end of thesubstantially vertical tubular member is coupled to a lower portion ofthe riser system such that, in use, fluid passing through the lowerportion of the riser system is arranged to enter the throughbore of thelower end of the substantially vertical tubular member in a fluid tightmanner; and an upper end of the substantially vertical tubular member iscoupled to an upper portion of the riser system such that, in use, fluidpassing through the upper end of the substantially vertical tubularmember is arranged to enter the upper portion of the riser system in afluid tight manner; and wherein the throughbore of the cross tubularmember is in fluid communication with the throughbore of thesubstantially vertical tubular member such that, in use, fluid producedfrom the lower portion of the riser system is permitted to flow throughthe end(s) of the cross tubular member and/or the upper end of thesubstantially vertical tubular member depending upon the configurationof valves attached thereto.
 45. A method of completing a riserinstallation comprising the steps of: lowering a riser system from avessel at the surface of a body of water to or in close proximity to thesurface at the bottom of the body of water; connecting a lower inlinevalve toward an upper end of the riser system; connecting a flowdiverter member above the said lower inline valve in the riser system;connecting at least one upper inline valve above the said flow divertermember in the riser system; connecting a telescoping member above thesaid upper inline valve in the riser system; connecting the lower end ofthe riser system to wellhead equipment provided at the head of a well;providing a valved tree member suitable for use in the region of a moonpool on the vessel, the valved tree member comprising one or more valvemembers adapted to selectively permit and prevent flow of fluidtherethrough, and one or more moveable stab members wherein the risersystem is run into the sea through a throughbore of the valved treemember; and aligning and coupling the flow diverter member with thevalved tree member and moving the said one or more stab members torespectively seal with at least one portion of the flow diverter memberto thereby provide a sealed fluid communication path between athroughbore of the riser system and the one or more valve members;wherein the flow of fluid produced from the upper end of the risersystem is capable of being selectively diverted from flowing up throughthe upper end of the riser system and instead is capable of beingselectively diverted through the said one of more stab members andthrough the said one or more valves of the valved tree member.